Methods and systems to synthesize terrain elevations under overpasses

Abstract

Systems, methods and computer storage apparatuses for synthesizing terrain elevations under overpasses are described herein. An embodiment includes identifying one or more spans across an overpass in an overpasses model, where the overpasses model includes information for one or more overpasses and respective locations and widths of the spans. The embodiment associates one or more terrain elevation values with the one or more identified spans, where the terrain elevation values can be included in an elevation model corresponding to the overpasses model. The embodiment further includes interpolating terrain elevation values for one or more points across the identified spans and updating the elevation model with the interpolated terrain elevation values.

Description

CROSS REFERENCE TO RELATED APPLICATIONS[0001]This application claims the benefit of U.S. Provisional Application No. 61 / 656,353, filed on Jun. 6, 2012, which is incorporated herein by reference in its entirety.BACKGROUND[0002]1. Field[0003]Embodiments generally relate to geographical terrain modeling.[0004]2. Background Discussion[0005]Digital Terrain Models (DTMs) are used for many applications in Geographical Information Systems (GIS) ranging from three dimensional (3D) terrain viewing applications to orthorectification (the geometric scaling of aerial photographs so they can be used as maps) and flood plain analysis. A DTM is a data file containing the elevation of the bare Earth (the terrain) at various points on the Earth's surface. As an example, elevations in a DTM can be specified in a square grid of cells with the grid represented in a coordinate system such as latitude and longitude. The elevation of terrain in a cell can be represented by an elevation value associated wit...

AI Technical Summary

Benefits of technology

The patent is about a way to create high-quality elevation models for overpasses by identifying spans across the overpass and assigning terrain elevation values to them. This allows for more accurate elevation of roads that have rapid elevation changes. The technique involves mapping spans in an overpass model and using interpolation to determine elevation values for points between spans. Overall, this makes it easier to create dynamic and accurate elevation models for overpasses.

Problems solved by technology

In some cases, which could occur, for example, when the occluded terrain has sharp features and elevation changes rapidly, these estimates are not accurate enough and manual editing of estimated terrain elevation values is needed to achieve desired accuracy.

This manual editing increases the cost of producing DTMs.

Furthermore, because the estimates are not sufficiently accurate, features rendered using these estimates appear to merge with surrounding terrain gradations.

This degrades user viewing experience.

In other applications (e.g., erosion modeling, flood plain analysis) inaccuracies in estimated elevations can cause erroneous results.

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